There is provided a novel method for producing solifenacin or a salt thereof which is useful as a medicine, particularly a therapeutic agent and/or a preventive agent for a urinary organ system disease such as pollakiuria or urinary incontinence. Illustratively, there are provided (1) a method for producing solifenacin in which 2-(1H-imidazolylcarbonyl)-1- phenyltetrahydroisoquinoline is used as the starting material, (2) a method for producing solifenacin succinate in which (1RS)-phenyltetrahydroisoquinoline-carboxylic acid quinuclidinyl ester is used as the starting material, (3) a method for producing solifenacin in which a lower alkyl quinuclidinyl carbonate is used as the starting material and (4) a method for producing solifenacin in which phenyltetrahydroisoquinoline-carboxylic acid secondary lower alkyl or tertiary lower alkyl ester is used as the starting material and allowed to react with an alkali metal lower alkoxide.
